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HomeMy WebLinkAbout2005-08-02 Engineering Review DEF SUB WITHDRAWN TOWN OF NORTH ANDOVER ENGINEERING REVIEW OF DEFINITIVE SUBDIVISION PLAN FOR CONFORMANCE WITH THE TOWN OF NORTH ANDOVER PLANNED RESIDENTIAL DEVOLEPMENT-ZONING BYLAWS SUBDIVISION RULES AND REGULATIONS AND STANDARD ENGINEERING PRACTICE i Site Plan Title: Eastwood(A Single Family Subdivision) VHB No„ 09280.03 Location: Salem Street Owner: Guy and Carol Richards, 2009 Salem Street,North Andover,MA Applicant: Chestnut Development LLC,231 Sutton Street,North Andover,MA Applicant's Engineer: Merrimack Engineering Services,66 Park Street,Andover,MA Review Date: June 6,2005 Vanasse Hangen Brustlin,Inc. (VHB) is providing a follow-up review of the Definitive Subdivision Plans and Drainage Study provided to date for the above referenced project.This review is conducted in accordance with the Town of North Andover Planned Residential Development-Zoning Bylaws,the Subdivision Rules and Regulations,Massachusetts Department of Environmental Protection(DEP) Stormwater Management Policy as applicable and standard engineering practice, VHB has received the following information for the follow-up review: ➢ Subdivision Plan: Eastwood(12 sheets)dated May 10,2005, ➢ Project Report on Drainage&Sedimentation Control revised April 26,2005, D Response to Comments letter dated May 16,2005, Response to North Andover DPW Ietter dated February 9,2005, VHB's original comments are shown below in normal font. VHB's second round of comments are shown in bold font immediately following the original comment. SUBDIVISION RULES AND REGULATIONS Section V. Definitive Subdivision Plan 1. (5.2.5.4.c.7) Proposed laterals with station and offset to hydrants are not shown on the profile. Addressed, 1 (5,23.4,00) Location and type of markings used for inspection not shown on profile. Addressed. 3. (5.2.5.5,a) -The typical section shows the proposed water line 10'LT,however it is shown on the plans at 7' RT. Addressed. -The Applicant appears to have labels from a previous project(Abbey Lane, Molly Towne Road) Addressed. -Proposed hydrant should be shown on the right side of the section. C:\1VI1 D0%V5\Temporary]nternel Flles\OLK6310\0928003-Eastwood-Follow_up,doc 1 Addressed. -A gas line is shown,is gas proposed? Addressed. 4. (5.2.5.5.b)This section requires that full flow capacity of inlet and outlet pipes and 10 yr storm water elevation be shown on the detention pond sections. Not Addressed. VHB offers the following comments: • The requested information has not been added to the plans, • The 100-yr storm water elevation that was previously shown should be included again, • The invert for the proposed 8"orifice appears to be incorrect, • VHB suggests renaming the detension basin details to be consistent with the names used on the plans and drainage reports (Detention Pond and Emergency Detention Pond). 5. (5.2.5.5.f)A Blow-off valve detail should be added to the plans. Addressed. 6. (5.2.5.5.h)A wheelchair ramp detail should be added to the plans. Addressed. 7. (5.4.4.6) The Applicant is requesting a waiver from submitting a Traffic Impact Analysis. Addressed. 8. (5.4.4.7) The Applicant is requesting a waiver from submitting a Cost/Benefit Analysis. Addressed. 9. (5.4.4.8) The Applicant is requesting a waiver from submitting a Cost Estimate. Addressed. 10. (5.4.4.9.i.a.i) This section asks for a brief description of the proposed Iand-disturbing activities,existing conditions and adjacent wetland areas that could be affected. 11. (5.4.4.91a.ii) This section asks for a description of any critical areas. 12. (5.4.4.91adii) This section asks for the expected Iength of destabilization. Comments 10,11 and 12 were partially addressed. The intent of these comments was to have the Applicant add the relevant information to the Erosion and Sedimentation Control Plan(Section 6.4)of the Project Report. Section VI.Requirements For Improvements And Design 13. (6.8.1)-The Applicant is requesting a waiver from the required 26' pavement width. Addressed. - The Applicant should provide more detailed information for the layout of the proposed granite edging at the intersection at Salem Street. VHB is unable to verify that curve radii in this section satisfies the Town's requirements. Partially Addressed. The radii were added to the plans,however Table IA of Section 6.8.1 specifies a minimum radius of 40'. The Applicant should revise the plans or request a waiver. - The Applicant is requesting a waiver for the required street length of 600'. Addressed. - The note on sheet 12 should read 922 feet in lieu of 600 feet(not 800 feet). Addressed. - The Applicant should verify that the Town in fact requires a minimum 120' diameter for the ROW and not a 120' radius. Addressed. 14. (6.8.9) It does not appear that the proposed profile has a 3% or flatter slope for the first 100'. Partially Addressed. Although there is a 3 foot grade difference after the first 100 feet of the subdivision roadway,indicating an average 311/o slope,the profile has been designed as a vertical curve and therefore does not have a continuous slope. The slope C.\W[N©OWS\Temporary Internet Piles\O[.K6310\0928DD3-Eastwood-Pollow_up.doe 2 of the vertical curve varies between 3%and 4.19%from Station 0+50 to Station 1+00. Given the steep topography of the site and the increased excavation that would result from any change(to make it slightly flatter within the first 100 feet)in profile,VUB suggests that the intent of this section has been met and no further response is necessary. 15. (6.9)--This section specifies that vertical granite curb be used at cul-de-sacs. Addressed, -Limits of granite curb and granite edging should be clearly indicated on the plans, as well as locations of proposed transition pieces. Addressed. -This section specifies that granite curb inlets be proposed at all catch basin on grades of over 6%. Addressed, -A granite curb inlet detail should be added to the plans. Addressed. 16. (6.11.2) The Applicant should add a sidewalk detail,specifying materials. S Addressed. 17. (6.12) The Applicant should provide a stone bound detail. Addressed, 18. (6.13.2) The Applicant should add the identification tape to the Subdivision Street Trench detail. Addressed 19. (6.14.5) The Applicant should verify whether the top grate of the outlet structure can be considered as an emergency spillway. Section 3B of the Massachusetts Department of Environmental Protection Stormwater Management policy states that"all wet ponds must have an emergency spillway capable of bypassing runoff from large storms without damaging the impounding structure." Addressed. 20. (6.14.10) It appears that access to Detention Basin 1 will be difficult for maintenance vehicles. The Applicant should provide an accessible path. Addressed. 21. (6.15.2) The Applicant should add hydrant markers to the Subdivision Sheet Hydrant Connection detail and associated labels to the Street Plan and Profile sheets. Addressed. 22. (6,18.2) The Applicant should verify that the proposed trees are acceptable. This section provides a list of recommended trees,it appears that only 2 of the proposed tree types are on this list. Not Addressed. The Applicant states in his response that the Landscape Architect will address. 23. (6.20) It does not appear the Applicant has proposed any signs. At a minimum,a stop sign should be proposed at the Salem Street intersection. The Applicant should verify whether other signs are needed. Addressed. 24. (6.21) Is street Iighting being proposed for the project? Addressed Appendix 1- Street Construction Specifications 25. (A.5) The Applicant should revise the Typical Section&Pavement Notes to show the required 12" of gravel sub base. Not Addressed. The Pavement Notes indicate an 8"depth of gravel sub base,this section specifies 12". C:\WJNDOWS\Temporary Internet Flles\OLK6310\0928003-Fastwood•Follow_up.doc 3 26. (A.7) The Applicant should revise the Typical Section&Pavement Notes to show the required 4" base course. Not Addressed. The Pavement Notes indicate an 3"base course,this section specifies 4"place in 2-2"layers. 27. (B.) The Applicant should specify curb and edging types on the Typical Section. Addressed. 28. (C.2) The Applicant should provide a sidewalk detail, with proposed material thicknesses. Addressed. Appendix 11-Surface Water Drainage Installation Specifications 29. (1) This section requires all drainpipes to be Class 4 concrete. The Applicant should justify the use of Class 3 pipes. Addressed. 30. (1.) This section requires that crushed stone conform to MHD Section M2.01.3, the Applicant should justify the use of M2.01.4. Addressed. Appendix IV-Tree Planting Specifications 31. (8.) A tree planting detail should be provided. Not Addressed. The Applicant states in his response that the Landscape Architect will address. Appendix V-Rules and Regulations Governing Storm Water Management 32. (3.G) A Nitrogen and/or Phosphorous Loading Report was not provided with this submission. Addressed. The Applicant is requesting a waiver from this requirement. 33. (5.0 The Applicant should revise the required Water Quality Volume calculation using 1" over impervious. Addressed. 34. (5.f) The Applicant should provide calculations showing how the provided Water Quality Volume was obtained. Addressed. 35. (5J) The outlet for Detention Pond#1 is flowing directly onto the adjacent property of Ruth Richards. The Applicant should justify that this property will not be affected by flooding from excessive runoff. Addressed. 36. (6.b.v) -The Applicant should provide calculations showing how the provided recharge volume was obtained. Addressed. -It is unclear what the 0.5"Rule calculation below the Recharge Volume calculation is used for. The Applicant should clarify. Addressed. -The Applicant should consider adding a column for the soil type multiplier in the Recharge Calculation chart. Addressed. General Comments C:\4Y1NDOWS\Temporary Internet Files\OLK63l0\0926003-Eastwood-Follow_up,doc 4 Y 5 37, The proposed sewer line along Salem Street connecting Eastwood to the Town's service is over 1600' long and has a slope of 0.4%. Has the Applicant discussed this sewer proposal with the Department of Public Works? Are there any alternatives? Addressed. 38, At the Salem Street intersection, the proposed sewer line is higher than the proposed water line. Addressed. 39. The proposed drainage line and both DMH4 and DMH5 are shown directly above the proposed water litre, The Applicant should revise the plans to avoid these conflicts. Addressed. 40. Should the dimensions labeled with*in the Subdivision Street Hydrant Connection detail be filled out? Addressed. 41. It is unclear where the Chain Link Fence and other associated details are proposed. Addressed. 42. It is unclear where Subdivision Street Stone for Pipe Ends,Typical Rip-Rap Swale and Typical Swale details are proposed. The previous details should be replaced with a Rip- Rap Apron detail. Addressed. 43, The Applicant should clarify the depth of the surface course in the Subdivision Street Trench detail. Addressed. 44. It is unclear what the notes on the bottom right of sheet 10 apply to, Addressed. General Drainage Comments 45. The Detention Basin Outlet Structure detail shows a 207.0' elevation,should this be adjusted? Addressed. 46. The Applicant should verify that all existing and proposed pipes can physically fit into proposed DMH6,on Salem Street. Addressed. 47, The Sediment Forebay Weir detail refers to sheet 7 for the Detention Basin Outlet Structure detail,however that detail appears on the same sheet. Addressed. 48. The invert for FES1 is lower than the bottom of Detention Basin 1. Addressed. 49. The Outlet Control Structure for Detention Basin#1 should not be placed in the sediment forebay. Addressed. 50. The Detention Basin Outlet Structure detail refers to sheet 6 for the Rip-Rap Weir. The detail appears on the same sheet. The Applicant should also make consistant the term used for the weir(Rip-Rap Weir vs Sediment>~orebay Weir). Addressed. 51, The Existing Drainage Divides plan should not show the proposed forebays and rip-rap areas. Addressed. 52. The Applicant used a time span of 5-20 hours in the Hydrocad model. Typically, a model should have a time span that goes from zero discharge to peak discharge,and C:\MNDOIVS\Temporary Internet Files\OLK6310\0929003-Eastwood-Foltaw_up.doc 5 back to zero discharge(beginning and ending of storm event). VHB suggests using a minimum time span of 0-24 hours. Addressed. VHB notes that only the Pre-Development model has been revised with the 0-24 hour timespan. No additional response is required, 53. The sheet flow slope used in the time of concentration calculation for Proposed Area F appears to be low. VHB scales the slope as closer to 0,2. Addressed. 54, The Applicant should verify the consistency between Proposed Detention Basin#2 Section and the Hydrocad model. The outlet invert and pipe lengths should be adjusted. Addressed. 55, Is it the Applicant's intent that the 4" orifice at elevation 122.0 be horizontal for the Detention Basin#1 Outlet Structure? Addressed, 56. There is a slight discrepancy between the rim elevation for CB3;the plans show 138.15, however the Storm Sewer Tabulation chart shows 138.20. Addressed. 57. The slope for the pipe connecting CB6 to DMH3 seems low, The Applicant should consider adjusting the inverts to make the slope closer to at least 0.5%. Addressed, 58. The flow through the pipe connecting DMH3 to FES1 is higher than its full capacity. The Applicant should adjust the inverts to accommodate the proposed flow, Addressed, Additional Comments 1. On sheet 4 of 12,the detention pond labels have not been revised from the first submission, The Applicant should revise and verify that all required information is shown on the plans. 2. The Applicant has provided a Stormceptor detail,model STC-900,in the Project Report,however a STC-450 appears to be proposed. The Applicant should add the appropriate detail to the plans. 3. The emergency spillway structure should not be within the sedimentation forebay. The Applicant should revise the plans, 4. Design Points A and G should not be added together. Design Point A is the existing drainage system and Design Point G is the adjacent property of Ruth Richards. The Applicant should revise the model or justify. 5. The slope shown for the outlet pipe in the Proposed Detention Pond 2 Section (S=0.015)is inconsistent with the slope used in the Hydrocad model (5=0.010). The Applicant should verify and revise. It is recommended that the Applicant provide WRITTEN RESPONSES to the issues and comments for all sections. Reviewed by: Date: Darryl Gallant 0\WINDOWS\Temporary InternetFltes\OLK4310\MB003-Eastwood-Eollow_up,doc 6 i Civil Engineer-Highway and Municipal Reviewed by: Date: Timothy B.McIntosh,P.E. Project Manager- Highway and Municipal C NIVINDOWS\Temporary Internet Files\aLK6310\0928003-Eastwood-Follow_up.doc 7